3种野生观赏蕨类植物的耐荫性评价

The Evaluation on the Shade Tolerance of Three Wild Ornamental Ferns

以狗脊(Woodwardia japonica)、盾蕨(Neolepisorus ovatus)、凤丫蕨(Coniogramme japonica)为材料,研究3种蕨类植物的耐荫能力。耐荫性试验设置透光率分别为50%、25%、8%的3个遮阴水平,测定不同遮阴情况下叶片形态(叶长、叶宽)、叶绿素含量、光合生理特性(净光合速率、蒸腾速率)的变化。结果表明:3种植物随着遮阴程度的加深,植株的叶片长度、宽度均发生不同的变化,且透光率25%、8%比50%时植物叶片长和宽有明显增长,盾蕨、凤丫蕨最适宜生长的相对光照强度为8%,狗脊为25%。叶绿素含量随遮阴程度的增加而增多,在8%光强时最高,50%光强时最低。3种蕨类植物的光合日变化曲线均呈双峰曲线,有明显的光合"午休"现象。净光合速率、蒸腾速率均随遮阴程度的加深而减少。结合指标变化,利用模糊数学中的隶属函数法对3种蕨类耐荫能力排序,依次为:盾蕨>凤丫蕨>狗脊。

The shade tolerance ofWoodwardia japonica,Neolepisorus ovatusandConiogramme japonicawere studied in this paper. 3 levels of light transmission rate of 50%, 25% and 8% was made in this experiment. Leaf length, leaf width, chlorophyll content, photosynthetic physiological characteristics （photosynthetic rate, transpiration rate were measured. The results indicated that the growth of leaf length and width changed along with the increase of the shading degree and the growth of leaf length and width at the levels of 25% and 8% of transmission rate of light were obviously higher than that at 50%. And 8% was the most suitable relative light intensity of growth ofNeolepisorus ovatusandConiogramme japonica, while that ofWoodwardia japonica was 25%. Besides, the chlorophyll content was increasing with more shading. The highest light intensity was at the level of 8% and the lowest was at 50%. The daily changes of photosynthetic rate in 3 ferns showed double-peak curves, with obvious phenomenon of photosynthetic “noontime rest”. The photosynthetic rate and transpiration rate were reducing along with shading increasing. According to the changes of indexes, the shading-tolerance abilities of different plants under shading stress by membership function were as follows：Neolepisorus ovatus〉Coniogramme japonica〉Woodwardia japonica.